Exodus 40:30-32

ECB(i) 30 And he sets the laver between the tent of the congregation and between the sacrifice altar and gives water there, to baptize. 31 And Mosheh and Aharon and his sons baptize their hands and their feet therein: 32 when they go into the tent of the congregation and when they approach the sacrifice altar, they baptize; as Yah Veh misvahed Mosheh.